Barcelona cannot afford to think about how Real Madrid's performance in El Clasico will change without Cristiano Ronaldo, says Marc-Andre ter Stegen.

Madrid's all-time leading goalscorer Ronaldo left the Santiago Bernabeu for Juventus in the off-season and was not adequately replaced, with Mariano Diaz the only addition up front for Julen Lopetegui.

Los Blancos ended a five-game winless streak, which included a run of four matches without scoring a single goal, by beating Viktoria Plzen 2-1 in the Champions League on Tuesday and now face the challenge of taking on LaLiga's leaders at Camp Nou.

Barca have a four-point advantage over their arch rivals and Ter Stegen warned his team-mates to pay attention to the talent in Madrid's line-up on Sunday, rather than who will be missing.

"I do not focus on a single player, Madrid have very good players with a lot of individual quality," the goalkeeper said in an interview with Club del Deportista.

"It's true Cristiano scored many goals and was a very important player for Real Madrid, so of course you will notice his departure from the club.

"We will see how it gets solved in the future. The important thing for us is to concentrate on ourselves to have a spectacular season and, with our great team, be better than all others and achieve objectives."

Germany international Ter Stegen joined Barca from Borussia Monchengladbach in 2014 and it was former director of football Andoni Zubizarreta who convinced him to depart the Bundesliga.

"I had been with the club for my whole life. It was my home, my favourite team and in my city. Then Andoni Zubizarreta appeared," he said.

"First he got in touch with my representative and then he and I met at a hotel in Germany and he explained what it meant to be a Barca goalkeeper, the history of the club and what they would expect from me.

"And he convinced me, with words and with feelings. Zubizarreta is a spectacular person. I had never been to Barcelona and everything he told me he got for me, so I accepted it and took the step for a new stage in my life. I made the right decision."

It was not a smooth transition for Ter Stegen, though, whose game time was limited with Luis Enrique preferring Claudio Bravo between the posts.

The former Gladbach keeper reiterated he came close to giving up and looking for a move away from Catalonia during that time.

He said: "As someone who wants to play in every game, it was a complicated situation and the competition with Claudio was not easy.

"I'm not going to deny there were times when I was thinking about leaving, looking for a solution."